Tunnel-drier.



a. H. BENJAMIN.

TUNNEL DRIER. APPLICATION FILED JAN-B, I9l8.

Patented Oct. 8, 1918.

1,280,642.. Fl G11.

UNITED sr GEORGE HILL-ARI) BENJAMIN, OF NEW YORK, N. Y.

TUNNEL-DRIER.

Specification of Letters Patent.

Patented Oct. 8, 1918.

Application filed January 8, 1918. Serial No. 210,896.

To all whom it may concern:

Be it known that I, GEORGE HILLARD BENJAMIN, a citizen of the United States, residing at New York, in the county and State of New York, have invented certain new and useful Improvements in Tunnel- Driers, of which the following is a specification.

My invention relates to driers of the kiln type. .In this type of drier, it has heretofore been'the practice to place the material to be dried upon cars, run the cars into the kiln, close the kiln, and then subject the material to the action of a body of air having a previously determined temperature, percentage of humidity, and circulatory movement. After the drying has been accomplished, the cars with the treated material are run out of the kiln. This method does not satisfy all of the required conditions.

In practice, it is often desirable to first subject the material to the action of a saturated, non-circulating body of air, for the purpose of heating the material up to a point where exudation will take place from the material, then to the action of circulating air currents heated to the same temperature and having less humidity, with the object of absorbing the exuded moisture from the material, then to the action of circulating air currents of lower temperature and higher humidity with the object of increasing the exudation with relatively smaller absorption of moisture than in the second step.

Further, as kilns are a long piece of apparatus, adapted to hold and treat large quantities of material, it is frequently desirable to Vary the temperatures, humidity and circulation along difl'erent zones in the kiln, according to the material which it is desired to treat in such zones.

My improved kiln is constructed to permit the above mentioned variations in the treatment to be carried into effect.

The accompanyin drawings, which are largely diagrammatic, will serve to illustrate my invention and the method of treatment employed, in which, Figure 1 is a longitudinal section.

Fig. 2 is a vertical section taken on the line II-II of Fig. 1.

Fig. 8 is a transverse section line III-III of Fig. 2.

Referring to the drawings. 5 indicates the body of the kiln, which may be of any suitable construction, made up of the top 6, side taken on the walls 7, and bottom 8. The side walls 7 are provided with inwardly projecting members 9, and disposed along the center of the kiln are vertical members 10. The urpose of the members 9 and 10, in con unction with the'cars carrying the material to be treated, is to divide the kiln longitudinally into a series of chambers or zones A, B, G, the number of chambers or zones corresponding to the length of the kiln. Situated on the bottom 8 of the kiln, are track rails 11 kiln, the kiln is actually divided into separate chambers A, B, C; at least sufficiently so, to prevent any considerable body of air, the temperature of such air, or the humidity of the air in ,one chamber, from afi'ectin g the body of air, temperature or humidity of the adjacent chamber.

Situated in the side walls 7, are air passages 16 which communicate at their upper ends 17 with the interior of the body of the kiln, and at their lower ends 18 with air passages 19 disposed longitudinally along the bottom of the center of the kiln. In the air passages 16 are heaters 20. These heaters are shown as formed of electric coils ar-- ranged in series across the kiln. I do not limit myself to the use of electric heaters, other forms of heaters may be employed.

Situated in the passage 19 is a coil 21, connected to a pipe 22,- through which cold water may be circulated as desired, the purpose of which will hereafter be explained. Situated also in the passage 19 is a spray pipe 23 adapted to project a downward spray of water 24. Located in the bottom of the passage 19, is a valve 25 which may be operated by means of a handle 26. The lower end of the passage 19 communicates with the passage 27, which is connected to the outlet end 28 of the pump 29. The inlet end 30 of the pump 29 is connected to a pipe 31, from which extends branch, pipes 32, each of which connects with the passage 19 in one of the chambers. Connected also to the passage 19 is a drain pipe 33, by means of which any water derived from the spray or otherwise, may be carried out of the apparatus.

The operation of my improved device is the interior of the apparatus at such time,

will be saturated with moisture, and the air heated by the heaters 20. At such time, the air will circulate very slowly if at all. When the material has reached the required temperature, the spray pipe 23 is shut down, and the spray decreased. At such time the air will take a circulatory course, flowing up the passage 16, across the material under treatment, and down the passage 19. where, owing to chilling of the air by the material under treatment due to evaporation of the moisture, a certain amount of water will be condensed in the lower part of the passage 19 and can be drawn off through the pipe 33. By regulating the spray 24, the amount of water in the air, air, may be regulated as desired.

Assuming now that it is desired to increase the absorption of water by increasing the rapidity of circulation of the air and decreasing the humidity. The valve 25 is then closed (see Fig. 2 at the center) and the pump 29 started, the spray 24 being regulated. The air is now drawn out of the kiln through the pipe 32 by action of the pump 29, and delivered into the kiln through the passage 27, from whence it passes through the passage 16 to passage 19,

the circulation being in the direction as previously described, and the air passing over the heaters as before.

Assuming now that it is desired to cool down the air, the heaters are then out of operation, the valve 25 closed (see Figs. 1 and 2 at the right) the spray out OK, and cold water circulated through the coils 21.

It will be understood, that owing to the fact that each of the chambers with the cars in position is practically a closed chamber, in one chamber (for instance A.) the material may be undergoing the heating operation; in chamber B, the moisture extraction operation, and in chamber C the cooling. It will be further understood, that by varying the temperatures, percentages of humidity, etc., various changes in temperature, humldity and degree of clrculation of the air currents as may be round necessary, may be regulated, according to the material under treatment.

It will be understood from the description given, that two methods of creating circulation are shown and described, one method being due to the water spray which acts as an air injector, and the other due to the action of the pump, which is positive:

It will be further understood that whereas 2'. 6., the humidity of the.

menace the apparatus is generally designed togact as a closed kiln, the materials may be given a step by step motion longitudinally through the kiln, and thus the material on a number of cars may be SUbJGCtQCl, while in chamber A to one treatment, in chamber B to another, and in chamber G to a third, before Having thus described my invention, I

claim: i

1. In a tunnel drier, the combination of an inclosing casing, air passages located transversely between the'center of the bottom of the kllll and the side walls of the easing, heating means in said air passages, and means for effecting a circulation of the air from the bottom of the kiln upward through such air passages, over the material in the i%n, and downward to the bottom of the n n.

2. In a tunnel drier, the combination of an inclosing casing, air passages disposed transversely between the center of the bottom of the kiln and the side walls of the casing, heating means in said air passages, a manually controlled valve, and duplicate fieans for effecting a circulation of air in the 3. Ina tunnel drier, the combination of an inclosing casing, a series of inwardly projecting members,a series of centrally disposed members, said members dividing the kiln longitudinally into a series of chambers, a duplicate trackway arranged longitudinally of the kiln, air passages disposed transversely between the center of the bottom of the kiln at each chamber and the side walls of the casing, heating means in such air passages, and means for efiecting a circulation of the air from the bottom of the kiln upward through such air passages to the sides ofthe kiln, over the material in the and downward to the bottom of the 4:. In a tunnel drier, the combination of an inclosing casing, a series of inwardly projecting members, a series of centrally disposed members, a duplicate trackway, a series of cars mounted on said trackway, air passages disposed between the center of the bottom of the kiln andthe side walls of the casing, heating means in said air passages, means for effecting a circulation of air wholly within the kiln, and means for effecting a circulation of air from the kiln, 1rivilthout the kiln and into and through the 5. In a tunnel drier, the combination of an inclosing casing, air passages disposed between the center of the bottom of the kiln and the side walls of the casing, heating menses means in said air passages, and a water spray for effecting circulation of the air from within the body of'the kiln, upward through the air passages and over the material in the kiln. V

6. In a tunnel drier, the combination of an inclosing casing, air passages disposed between the center of the bottom of. the kiln and the side walls of the casing, air cooling devices. situated in said air passages, together with means for conveying from the interior of the kiln the water condensed from the air when the cooling devices are in operation.

7. In a tunnel drier, the combination of an inclosing casing, a series of inwardly projecting members, a series of centrally disposed members, duplicate trackways, cars mounted on said trackw'ays, said cars constructed to substantially close the space'in,

the interior of the kiln intervening between I the top of the casing and the inwardly pro- Jecting and centrally disposed members, air passages transversely located between the center of the bottom of the kiln and the side Walls of the casing, heating means in said ,of said zones for heating air, together with means in each of said zones for circulating air, means for humidifying air, together with means in each of said zones for regulating the temperature, circulation and humidity of theair in each zone, independently of that of the other zones.

In testimony whereof, I aifix my signature in the presence of two witnesses.

GEORGE HILLARD BENJAMIN. I Witnesses:

HELEN E. Komnscn, LESTER BEARDSLEY. 

